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| 2. |
- Disch, Sabrina, et al.
(författare)
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Structural diversity in iron oxide nanoparticle assemblies as directed by particle morphology and orientation
- 2013
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 5:9, s. 3969-3975
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Tidskriftsartikel (refereegranskat)abstract
- The mesostructure of ordered arrays of anisotropic nanoparticles is controlled by a combination of packing constraints and interparticle interactions, two factors that are strongly dependent on the particle morphology. We have investigated how the degree of truncation of iron oxide nanocubes controls the mesostructure and particle orientation in drop cast mesocrystal arrays. The combination of grazing incidence small-angle X-ray scattering and scanning electron microscopy shows that mesocrystals of highly truncated cubic nanoparticles assemble in an fcc-type mesostructure, similar to arrays formed by iron oxide nanospheres, but with a significantly reduced packing density and displaying two different growth orientations. Strong satellite reflections in the GISAXS pattern indicate a commensurate mesoscopic superstructure that is related to stacking faults in mesocrystals of the anisotropic nanocubes. Our results show how subtle variation in shape anisotropy can induce oriented arrangements of nanoparticles of different structures and also create mesoscopic superstructures of larger periodicity.
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| 3. |
- Dish, Sabina, et al.
(författare)
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Quantitative spatial magnetization distribution in iron oxide nanocubes and nanospheres by polarized small-angle neutron scattering
- 2012
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 14, s. 013025-
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Tidskriftsartikel (refereegranskat)abstract
- By means of polarized small-angle neutron scattering, we have resolved the long-standing challenge of determining the magnetization distribution in magnetic nanoparticles in absolute units. The reduced magnetization, localized in non-interacting nanoparticles, indicates strongly particle shape-dependent surface spin canting with a 0.3(1) and 0.5(1) nm thick surface shell of reduced magnetization found for similar to 9 nm nanospheres and similar to 8.5 nm nanocubes, respectively. Further, the reduced macroscopic magnetization in nanoparticles results not only from surface spin canting, but also from drastically reduced magnetization inside the uniformly magnetized core as compared to the bulk material. Our microscopic results explain the low macroscopic magnetization commonly found in nanoparticles.
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| 4. |
- Kautonen, Teemu, et al.
(författare)
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‘Involuntary self-employment’ as a public policy issue : A cross-country European review
- 2010
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Ingår i: International Journal of Entrepreneurial Behaviour & Research. - : Emerald. - 1355-2554 .- 1758-6534. ; 16:2, s. 112-129
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – There is growing political interest in new forms of precarious self-employment located in a “grey area” between employment and self-employment. A wide range of concepts has been used to debate this issue, and this paper aims to clarify these debates through the concept of involuntary self-employment.Design/methodology/approach – The paper reviews the empirical, conceptual and legal-policy approaches to involuntary self-employment via three country case studies in Finland, Germany and the UK. A range of relevant domestic academic literature, articles in the media, selected key expert interviews, and policy and legal documents are employed.Findings – Conceptual clarity regarding involuntary self-employment is achieved through a discussion of two aspects of the phenomenon: the characteristics of involuntariness from a motives-based perspective, and the legal/economic perspectives and policy issues. The motives-based analysis argues that involuntariness as such does not seem to have severe implications on the individuals' well being, given that the individual earns a satisfactory livelihood from her or his business activities. The discussion of the characteristics of and regulation related to working arrangements in the “grey area” between employment and self-employment, where the self-employed individual is strongly dependent on the principal, shows that it is very difficult to regulate quasi self-employment without harming “voluntary” forms of enterprise and inter-firm cooperation at the same time.Originality/value – The key contribution of the paper is to facilitate a foundation for subsequent empirical research and policy development.
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| 5. |
- Maezawa, Yoshiro, et al.
(författare)
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Loss of the Podocyte-Expressed Transcription Factor Tcf21/Pod1 Results in Podocyte Differentiation Defects and FSGS
- 2014
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 25:11, s. 2459-2470
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Tidskriftsartikel (refereegranskat)abstract
- Podocytes are terminally differentiated cells with an elaborate cytoskeleton and are critical components of the glomerular barrier. We identified a bHLH transcription factor, Tcf21, that is highly expressed in developing and mature podocytes. Because conventional Tcf21 knockout mice die in the perinatal period with major cardiopulmonary defects, we generated a conditional Tcf21 knockout mouse to explore the role of this transcription factor in podocytes in vivo. Tcf21 was deleted from podocytes and podocyte progenitors using podocin-cre (podTcf21) and wnt4-cre (wnt4creTcf21) driver strains, respectively. Loss of Tcf21 from capillary-loop stage podocytes (podTcf21) results in simplified glomeruli with a decreased number of endothelial and mesangial cells. By 5 weeks of age, 40% of podTcf21 mice develop massive proteinuria and lesions similar to FSGS. Notably, the remaining 60% of mice do not develop proteinuria even when aged to 8 months. By contrast, earlier deletion of Tcf21 from podocyte precursors (wnt4creTcf21) results in a profound developmental arrest of podocyte differentiation and renal failure in 100% of mice during the perinatal period. Taken together, our results demonstrate a critical role for Tcf21 in the differentiation and maintenance of podocytes. Identification of direct targets of this transcription factor may provide new therapeutic avenues for proteinuric renal disease, including FSGS.
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| 6. |
- Mohl, Melinda, et al.
(författare)
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Titania nanofibers in gypsum composites : an antibacterial and cytotoxicology study
- 2014
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Ingår i: Journal of Material Chemistry B. - : Royal Society of Chemistry. - 2050-750X .- 2050-7518. ; 2:10, s. 1307-1316
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Tidskriftsartikel (refereegranskat)abstract
- Further developments of antibacterial coatings based on photocatalytic nanomaterials could be a promising route towards potential environmentally friendly applications in households, public buildings and health care facilities. Hereby we describe a simple chemical approach to synthesize photocatalytic nanomaterial-embedded coatings using gypsum as a binder. Various types of TiO2 nanofiber-based photocatalytic materials (nitrogen-doped and/or palladium nanoparticle decorated) and their composites with gypsum were characterized by means of scanning (SEM) and transmission (TEM) electron microscopy as well as electron and X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) techniques. These gypsum-based composites can be directly applied as commercially available paints on indoor walls. Herein we report that surfaces coated with photocatalytic composites exhibit excellent antimicrobial properties by killing both methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) under blue light. In the case of MSSA cells, the palladium nanoparticle-decorated and nitrogen-doped TiO2 composites demonstrated the highest antimicrobial activity. For the MRSA strain even pure gypsum samples were proven to be efficient in eradicating Gram-positive human pathogens. The cytotoxicity of freestanding TiO2 nanofibers was revealed by analyzing the viability of HeLa cells using MTT and fluorescent cell assays.
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| 7. |
- Pranzas, P. Klaus, et al.
(författare)
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Characterization of Hydrogen Storage Materials and Systems with Photons and Neutrons
- 2011
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 13:8, s. 730-736
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Tidskriftsartikel (refereegranskat)abstract
- Complex hydrides are very promising candidates for future light-weight solid state hydrogen storage materials. The present work illustrates detailed characterization of such novel hydride materials on different size scales by the use of synchrotron radiation and neutrons. The comprehensive analysis of such data leads to a deep understanding of the ongoing processes and mechanisms. The reaction pathways during hydrogen desorption and absorption are identified by in situ X-ray diffraction (XRD). Function and size of additive phases are estimated using X-ray absorption spectroscopy (XAS) and anomalous small-angle X-ray scattering (ASAXS). The structure of the metal hydride matrix is characterized using (ultra) small-angle neutron scattering (SANS/USANS). The hydrogen distribution in tanks filled with metal hydride material is studied with neutron computerized tomography (NCT). The results obtained by the different analysis methods are summarized in a final structural model. The complementary information obtained by these different methods is essential for the understanding of the various sorption processes in light metal hydrides and hydrogen storage tanks.
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